1. Field of the Invention
The present invention relates to a regenerative refrigerator that uses a refrigerant gas such as helium gas and includes a regenerator containing a regenerator material, and to a partitioning member that partitions off the regenerator material provided in the regenerative refrigerator.
2. Description of the Related Art
A regenerative refrigerator that uses a refrigerant gas such as helium gas and has a regenerator containing a regenerator material is used to attain a cryogenic temperature of approximately 4 K, for example. Further, for example, a Gifford-McMahon (GM) refrigerator is used as the regenerative refrigerator.
The GM refrigerator generates cold heat by supplying an expansion space formed in a cylinder with a refrigerant gas composed of, for example, helium gas from a compressor and causing the fed refrigerant gas to expand in the expansion space. Usually, the GM refrigerator has multiple stages in order to attain cryogenic temperatures with the generated cold heat.
Each of the stages of the GM refrigerator includes a cylinder and a displacer provided in the cylinder. The displacer is so provided inside the cylinder as to be reciprocatable along the cylinder. An expansion space is formed between one end of the displacer and the cylinder. Further, a refrigerant gas passage for feeding a refrigerant gas into and discharging the refrigerant gas from the expansion space is defined inside the displacer. Further, a regenerator material that comes into contact with the refrigerant gas to store cold heat is contained inside the displacer.
Inside such a displacer, a partitioning member that partitions off a regenerator material or separates regenerator materials is provided in order to fill a predetermined space with a regenerator material or to prevent mixture of regenerator materials in the case of using multiple kinds of regenerator materials. (See, for example, Japanese Laid-Open Patent Application No. 2004-293924.)